Date:         Fri, 20 Jul 2007 16:19:55 -0500
Reply-To:     joel walker <jwalker17@EARTHLINK.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         joel walker <jwalker17@EARTHLINK.NET>
Subject:      Re: fuel pump relief valve?
Comments: To: Sam Payne <bungeegull@HOTMAIL.COM>
Content-Type: text/plain; format=flowed; charset="Windows-1252";
              reply-type=original

> Does anyone out there know if an '86 vanagon fuel pump has a
> built-in
> pressure relief valve? If it does, what should maximum pressure be
> before
> the valve opens? I found no mention of this in Bentley.

well ... apparently there is such an animal in SOME fuel injection
systems ... (way down at the bottom of the web page) ...
http://www.v8sho.com/SHO/fuelsysdesc.html
but on that one, it's on the fuel injector rail, not in the pump.
so it works sort of as a rev-limiter, in a way: can't go too fast
cause you can't get too much fuel.

and i've noticed several aviation finds on google that mention
pressure relief valves. i imagine it would be a lot more important to
have such things at 10,000 feet than down on the  highway. :)

and it seems that porsche CIS injection has one in its pump "in case
of restrictions".
http://www.ncr-pca.org/tech/tech-cis.htm

and the bosch k-jetronic seems to have one. and since this pump is
almost identical to the one used in the L-jetronic (which is the
granddaddy of our digifant (and the daddy of the digijet)), it's
highly likely that, yes, our digifant fuel pumps DO have a "pressure
limiter" valve inside them. http://www.auto-solve.com/mech_inj.htm
but notice the 2nd part of the first section of The Fuel Pump. the
pressure limiter is set at 8bar or 120psi ... you were still short of
the pressure needed to kick the relief valve into action.

learn something new every day. how bout that. :)

unca joel